Carnivorous plants tend to grow in very poor soils and the habitats of carnivorous plants usually involve wet, low-nutrient sites including bogs, swamps, waterbodies, forests and sandy or rocky sites. The 630 species of carnivorous plants can be found on every continent except Antarctica. Because of where they live, they attract, trap and digest animals for the nutrients they contain. Although most carnivorous plants consume insects, larger plants are actually capable of digesting reptiles and small mammals, and smaller plants specialize in digesting single-celled organisms.
Being carnivorous is great for a nutrient kick, it doesn’t replace the need for photosynthesis and root systems. Being carnivorous simply helps the plant make the most of all available resources.
Carnivorous plants use a variety of strategies to lure prey into their traps; some produce strong-smelling nectar and have intense coloration that mimic flowers. Others camouflage themselves so that victims blunder into them. These plants keep prey species separate from pollinating insects by growing their true flowers at the end of long stalks, which blossom as far as possible from the tempting and deadly digestive organs. Most carnivorous plants produce digestive enzymes that dissolve their prey into a nutritious bug soup.
Carnivorous plants can be classified into five groups based on their trapping methods: pitfall, adhesive, snap, snare and suction. Venus Flytraps catch their prey in snap-closing traps made of modified leaf blades. Drawn in by the promise of a “flower” the insect or small reptile entering the trap stimulates sensitive trigger hairs on the inside of the trap. Though these plants have no brain or nervous system, the hairs send an electrophysiological impulse, an action potential, to tell the leaf blades to snap shut snare the visitor, but only once the plant is sure there is a meal there. Once the prey is secured in the trap, it secretes a digestive fluid to resorb the animal protein.
This lab focuses on the action potentials generated during the stimulation of the spiny hairs on the inside of the trap and makes for an excellent comparative physiology lab with frogs, earthworms and humans.
Physiology in Action
Catching prey requires Venus Flytrap (Dionaea muscipula) to snap down quickly and then carry
out the energy-intensive process of digestion. To balance the costs and benefits of eating meat,
the plants have developed a counting system to identify real prey from false alarms, according to
a new study.
The carnivorous Venus Flytrap (Dionaea muscipula) harbors multicellular trigger hairs designed
to sense mechanical stimuli upon contact with animal prey. At the base of the trigger hair,
mechanosensation is transduced into an all-or-nothing action potential (AP) that spreads all over
the trap, ultimately leading to trap closure and prey capture.
Reusable Electrodes for the Venus Fly Trap. 2 AgCL button electrodes and 1 silver wire electrode, with adhesive gel.